The human skin is subject to certain aging processes, some of which are attributable to intrinsic processes (e.g., chronoaging) and some of which are attributable to exogenous factors (e.g., photo-aging). In addition, temporary or even lasting changes to the skin can occur, such as acne greasy or dry skin, keratoses, rosacea, light-sensitive, inflammatory, erythematous, and allergic or autoimmune-reactive reactions, such as dermatosis and photodermatosis.
The consequences of the above-mentioned ageing processes can include thinning of the skin, weaker interlacing of epidermis and dermis, and a reduction in the number of cells and the supplying blood vessels. This often results in the formation of fine lines and wrinkles, and pigment defects can occur.
Retinoids, such as retinoic acid, retinol and esters thereof, and tazorotene, act on the differentiation of epithelial cells and are therefore employed for the prophylaxis and treatment of numerous phenomena, which impair the skin state. For example use against acne, psoriasis, senile keratosis, skin discoloration and wrinkles has been described. See, e.g., PCT Patent Applications Nos. WO 93/19743 and WO 02/02074.
Applicants have unexpectedly discovered that beta-aminoisobutyric acid and its derivatives induce a significant, synergistic increase of retinoid activity.